Method of and apparatus for removing entrained moisture from oil



T. J. BROIDRICK Filed July 24, 1955 Fl. i

METHOD OF AND APPARATUS FOR REMOVING ENTRAINED MOISTURE FROM OIL May 28,1957 k w M MW 2 4 w M r a $55 6 "6% fl i n 1:1: if 5 Hum @J 3 m1: do a r2 4 3 6 A 9 6 MM a B v owwm m o 2 T n 2 M m fig i2 7 G L wvoaw v UJ 2 kI g \H I Q j 5 T L F w w Patented May 2a, 1957 METHOD OF AND APPTUS FORREMOVING ENTED MOISTURE FROM 01L Thomas J. Broidrick, deceased, late ofEast Orange, N. J.,

Application July 24, 1953, Serial No. 370,187 4 Claims. (Cl. 210-83)This invention relates to a novel method and apparatus for removingentrained or occluded moisture from substantially water-immiscibleliquid compositions.

While the invention may be advantageously employed for the removal ofentrained or occluded moisture from various Water-immiscible liquids,such as vegetable oils and the like, it is particularly useful inremoving moisture which causes haze to appear in fuel oils, lubricatingoils, diesel oils and the like, and is hereinafter described withreference to the treatment of such liquids. But, as will be obvious fromthe description that follows, the method and apparatus of this inventionare broadly applicable to the removal of entrained moisture fromwater-immiscible compositions which are liquid at the operatingtemperature and are not injured by intimate contact with the air orother gas used in the method as the moisture absorbing and removingagent.

Fuel oils, lubricating oils, diesel oils and the like, during storageand transportation, usually develop haze, that is, water clouds due toentrainment of moisture particles. Also, as a consequence of certain oilrefinery operations, the amount of haze in the oils is frequentlyincreased.

Oil refineries have, for many years, experienced considerable difiicultyin removing haze from their oils for the purpose of obtaining clear andbright oils. The methods heretofore employed by such refineries for theremoval of haze have been unsatisfactory because of high initial,maintenance and operating costs.

The present invention provides a novel, eflicient and relativelyinexpensive method and apparatus for dehazing such oils and equivalentwater-immiscible liquids.

Accordingly, the primary object of this invention is to provide animproved method and apparatus for removing entrained or occluded mosturefrom substantially Water-immiscible liquid compositions, such as varioushydrocarbon oils.

Another object of the invention is to provide an improved method fordehazing oils, whereby to render the same brighter and clearer.

A further object of the invention is to reduce the moisture content ofsubstantially water-immiscible liquid compositions, such as oils havingentrained moisture, in a simple, effective and economical manner.

To the end that the foregoing objects may be readily attained, apreferred and recommended method of practicing the invention comprisessimultaneously introducing a moisture-containing hydrocarbon oil and airinto a treating zone. The oil is subjected to vigorous mechanicalagitation in the treating zone, thereby elfecting intimate contactbetween the air and the oil, the ingredients; and the mixture issuccessively compressed and permitted to expand to effect separation ofmoisture particles from other components of the composition andabsorption of the moisture particles by the air in the mixture. The aircarrying absorbed moisture particles produces foam bubbleswhich rise tothesurface of the oil in the treating zone. The foam and treated oil aretransmitted into a settling tank, where the foam 7 is permitted tobreak, allowing to obtain a mixture of i the air-absorbed moisture toescape, and the treated oil, now in clear, bright condition, iswithdrawn.

The oil admitted into the treating zone is at a temperaturesubstantially below its flash point and preferably Within the range ofto F., depending on the type and characteristics of the oil. The airadmitted into the treating zone may be at atmospheric pressure andtemperature. While air is preferred for reasons of economy, any othersuitable gas that is non-reactive with oil and that is capable ofabsorbing moisture may be used in lieu of air. Therefore, the expressionair, as used in this description and in the claims, has reference toair, gases that may be used in place of air, or combinations thereof.

The compression and expansion of the mixture, referred to above, iscaused in part by the forcing of the mixture between the staves of therotor and stator and in part by the turbulence, or eddying wake, due tothe mixture flowing around the staves, thereby creating varyingpressures within the mixture.

The enumerated objects, as well as other objects, together with theadvantages attainable by the practice of this invention, will be readilyunderstood by persons skilled in the art, from the detailed descriptionthat follows, taken in conjunction with the accompanying drawing, thatrespectively describe and illustrate a preferred arrangement ofapparatus for carrying out the invention.

In the drawing:

Fig. 1 is a generally schematic representation of the apparatus, certainparts being shown in central, vertical cross-section.

Fig. 2 is an enlarged view of a portion of Fig. l, certain additionalparts being shown in vertical cross-section; and

Fig. 3 is a view taken along line 3-3 of Fig. 2, parts being omitted forbetter illustration of other parts.

Referring now to the drawing, wherein like reference numerals denotecorresponding parts in the various views, and more particularly to Fig.1, a supply conduit 5 transmits oil to be treated from a source (notshown) to a settling tank 6. Tank 6 is utilized in instances where theoil contains free water. The free water settles from the oil in thistank and is withdrawn by way of a drain conduit 7, which establishescommunication between the bottom of the tank and a water dischargeconduit 8. Withdrawal of water from tank 6 is controlled by a valve 9 inconduit 7. Oil and residual entrained moisture collect in the upperportion of the settling tank and are Withdrawn by way of an oil feedconduit 10.

If the oil to be treated does not contain a substantial quantity of freewater, it may be transmitted from conduit 5 to conduit 10 by Way of aconduit 11 that bypasses tank 6. Three-way valves 12 and 13, at thejunctures of conduit 11 with conduits 5 and 10, respectively, are portedso as to control the flow of oil either through the tank or through thebypass conduit, as desired. In either case, the oil is next transmittedinto a treating zone 14.

The treating zone comprises a tank 15 having an open top, across whichthere is provided a pair of angle supports 16. A plate 17 having acentral opening 18 (Fig. 2) is secured to the angle supports. Mounted onplate 17 is a driving unit 20 that includes a base plate 21, having acentral opening 22 aligned with opening 18 in plate 17, a plurality ofspaced upstanding support members 23 and an explosion-proof electricmotor 24, carried by members ing shaft 25 that extends into tank 15.

tioned in tank 15, whereby to impart vigorous agitation 23. The motorincludes a rotary drivto and effect compression of materials admittedinto the tank. This means, which will now be described, comprises arotor 26 having a shaft 27 secured to the lower end of shaft 25. androtatable therewith. The

through the openings between the staves of the rotor and the stator and,in the course of such movement, is compressed and then permitted toexpand. As the mixture is forced through the openings between the stavesof fowl? also includes P of P Q pfl p fi. the rotor and those of thestator, oil-moisture or moisf 29 that are ecured PP ends; of Shaftture-oil cells contained in the mixture are broken down, SPlder has anm30 and PTOVlded P y effecting separation 'of moisture particles fromthe oil. f Upenlngs SPldeT 29 Preferably ldefltlcfil with As the mixtureexpands, onv passing outwardly beyond spider 28 and 18 provided wlth arim 32v and openlngs the stator staves, the moisture particles areabsorbed by 33. Disposed between rims 30 and 32 isv a plurality of theair, in the form, of foam which rises in tank 15. This cylindrical,spaced-apart staves 34, best shown in Figs. foam and treated oil aretransmitted by spillway 42 into 2 and 3. sump tank 43, where the foambreaks and escapes to Coaxial with and spaced from rotor 26 IS a statonary the atmosphere and the treated oil, now in bright and stator 35,which includes a pluralityof legs 36, a pair of clear condition, iswithdrawn by way of conduit 44. parallel rings 37 and 38 and a pluralityof cylindrical Examples of refinery runs and results obtained by staves39. These staves are parallel and spaced from treating hydrocarbon oilsin accordance with this inveneach other and from staves 34. Staves 34and 39-. are tion and employing systems of apparatus, as above desimilarin configuration and relative position to the correscribed, are setforth in the following tables:

Run No 1 2 a 4 a V 5 6 Duration of Run in Hours 2 .75 2 2 2.25 3. ChargeStock Eastern Vene- Eastern Yene- Southern Lou- Kuwait Virgin UntreatedWestern Venezuela Virgin zuela V1rginisiana Virgin Oil. Catalytic zuelaVirgin Oil. 011. 011. Cracked Oil. Oil. Temperature oi Stock in TreatingZoneinF. 10 1 99. 04, 108 109 108.

a b ab a b a b a b a (2 Moisture Content of ChargeStock in ppm... 174236 103 253 88 91" 172 613 233 464 120 194 Moisture Content of Productin p.p.m 104 105 67 86 62 63 148. 148 96 128 61 66 Moisture Removed inp.p.m- 70 13 36 167. 26 28 24 465 137 336 59 128 Weight Percent of WaterRemoved 40.2 55.5 35.0 66.0' 29.5 30.8 14.0 75.9 5&8 72.5 49.2 66.0

In the table P. p. m. denotes parts of moisture per million parts ofoil, a refers to composite specimens. 7) refers to averages of specimenstaken at the start, middle and end of the corresponding run.

spending staves disclosed in Fagergren Patent 1,963,122, to whichreference may be had for further details, of construction.

An imperforate tubular air chamber 40- is positioned between stator ring37 and plate 17. Air from the atmosphere is admitted into the rotor byway of the spaces between members 23, opening 22 in plate 21 opening 18in plate 17, the interior of air chamber 40v and openings 31 in spider28, in the order named.

As is shown in Fig. 1, feed conduit 10 extends downwardly along the sidewall of tank 15 and thence along the bottom wall of that tank,terminating at stator 35,

whereby to discharge oil to be treated in the, region directly belowrotor 26. Also, water discharge conduit "l he solubility of water inhydrocarbon oil is commonly known as thehaze point of the oil. Thisvaries with 8 communicates with the interior of tank '15 andv is provided with a control valve 41 for withdrawingaccumulated water from thistank, as required.

A spillway 42 (Fig. 1) is secured to tank 15 and empties into a suitablereceptacle, such as a sump tank 43, which receives foam and, treatedliquid from the upper portion of tank 15. Treatedoil is withdrawn fromtank 43 by a conduit 44.

For the purpose of briefly outlining themode, of opera:

tion of the above described system of apparatus, it is first assumedthat oil, which does not contain an appre: ciable quantity of freewater, is being transmitted by feed conduit 10 to the region of tank 15below rotor 26, and that driving unit 20 is in active service, therebyirr parting rotation to the rotor. The oil moves upwardly into the rotorthrough rotor imparts vigorous stirring and agitation to the oil in thestator. Due to the rapid movementof the, oil in the rotor, a partialvacuum is created therein and air is inspirated into the rotor throughthe openings. earlier described. The air so admitted into the rotor isbrought openings 33 in spider 29. The

into intimate contact with the oil and dispersed therein,

oil and air is moved outwardly, by,- centrifugal action the temperatureof the oil. At the haze point tempera ture' of 0 F., hydrocarbon oilsnormally contain about 10 parts of moisture per million parts of oil; athaze point temperature of 30 F parts of moisture; and at haze pointtemperature of 50 F;, parts of moisture. A haze point temperature of-30" F. is considered excellent, while one of- 50 F. is consideredsatisfactory.

The extent of moisture removal by the practice of this invention isdependent on a number of factors, including the characteristics of theparticular; composition undergoingtreatment, the temperature of thecomposition during treatment, the rate of flow, the size and. design ofthe treating zone and of the rotor-stator unit, the speedof rotation ofthe rotor and the amount of airintroduced into the composition. Therefinery runs identified in the foregoing tables employed a tank,corresponding'to tank 15, that was 18" wide, 23" long and 14" deep, adriving unit having a horsepower, explosion-proof, electric motoroperating at a speed of 1750 R. P. M., and a rotorstatorunitapproximately 7" wide. The referred to charge stocks were continuouslyintroduced into tank 15 at a rate of from 2 to 4 gallons per minute,depending onthe particular stock, and were successfully dehazed attreating temperatures of from 99 to 118 F.

Treating equipment having a considerably greater capacity than that justdescribed has also been used. to effectively and economically dehazeoils in accordance with this invention. One arrangement of suchequipment includes a treating tank, corresponding to tank 15, which is66 wide, 84" long and 38" deep, a driving unit having a 15 horsepower,explosion-proof, electric motor operating at a speed of 490 R. P. M.,and a rotor-stator unit approximately 24" wide, Tests have demonstratedthat this equipment adequately dehazes oil at the rate of from 200 to.500 barrels per hour depending on the type and, characteristics of, theparti ular oil; and its temperature;

during treatment. For example, No. 2 heating oil having a heavy moisturecloud was transmitted into this equip ment at a rate of 450 barrels perhour and effectively dehazed at a temperature of about 118 F. to obtaina bright, clear product. Also, a light lubricating oil wassatisfactorily dehazed when run through the equipment at the rate offrom 200-300 barrels per hour and at a treating temperature below itsflash point and within the range discussed earlier herein.

From the foregoing, it is believed that the method and apparatus forpracticing the instant invention will be readily comprehended by personsskilled in the art. It is to be clearly understood, however, thatvarious changes in the apparatus herewith shown and described and in themethod of practicing the invention, outlined above, may be resorted towithout departing from the spirit of the invention as defined by theappended claims.

What is claimed is:

1. In a method for removing moisture occluded in a substantially waterimmiscible liquid composition which is substantially free from waterreadily separable by gravity, the steps of (1) agitating said moisturecontaining liquid composition in the presence of gas to which saidliquid composition is chemically substantially inert at the operatingtemperature to form an intimate mixture of said liquid composition withdispersed gas in the form of fine bubbles and cause repeated expansionsand contractions in the mixture thereby contacting and evaporatingoccluded moisture into the dispersed bubbles of gas, (2) separating thedispersed gas carrying absorbed moisture from the unevaporatedconstituents in the mixture and (3) recovering all of the unevaporatedconstituents which constitute the relatively water-free water immiscibleliquid product.

2. The method according to claim 1, in which the substantially waterimmiscible liquid composition is a liquid hydrocarbon oil composition,the gas is air, and the operation is conducted at a temperature belowthe flash point of said oil composition.

3. The method according to claim 1, in which the substantially waterimmiscible liquid composition is a liquid hydrocarbon oil composition,the gas is air drawn in from the surrounding atmosphere, and theoperation is conducted at a temperature below the flash point of saidoil composition and within a temperature range of to F.

4. In apparatus for removing occluded Water from a water immiscibleliquid free from water readily separable by gravity, a tank, means forcontinuously introducing the liquid to be treated at a predeterminedrate into said tank near the bottom thereof, agitating means andassociated baflle means for defining and maintaining a treating zone ofviolent agitation and turbulence in said tank substantially above thebottom and substantially below the top thereof, means associated withsaid agitating means for drawing into said zone of agitation andturbulence the liquid to be treated and a gas in order to form anintimate turbulent mixture of said liquid and finely dispersed gas, arelatively quiescent zone in said tank into which said mixture oftreated liquid and finely dispersed gas can flow from said zone ofagitation and turbulence and rise by gravity to the top of said tank,thereby allowing at least some of the dispersed gas to separate from thetreated liquid by gravity, and means connected near the top of said tankby means of which the mixture of treated liquid and remaining gascontinuously overflows to a receptacle wherein the remaining gas admixedtherewith can separate by gravity and all unevaporated constituents ofthe treated liquid can be recovered.

References Cited in the file of this patent UNITED STATES PATENTS2,220,574 Little et a1 Nov. 5, 1940 2,274,658 Booth Mar. 3, 19422,342,024 Walker Feb. 15, 1944 2,436,375 Booth et al Feb. 24, 19482,451,144 Aubrey Oct. 12, 1948

1. IN A METHOD FOR REMOVING MOISTURE OCCLUDED IN A SUBSTANTIALLY WATERIMMISCIBLE LIQUID COMPOSITION WHICH IS SUBSTANTIALLY FREE FROM WATERREADILY SEPARABLE BY GRAVITY, THE STEPS OF (1) AGITATING SAID MOISTURECONTAINING LIQUID COMPOSITION IN THE PRESENCE OF GAS TO WHICH SAIDLIQUID COMPOSITION IS CHEMICALLY SUBSTANTIALLY INERT AT THE OPERATINGTEMPERATURE TO FORM AN INTIMATE MIXTURE OF SAID LIQUID COMPOSTION WITHDISPERSED GAS IN THE FORM OF FINE BUBBLES AND CAUSE REPEATED EXPANSIONSAND CONTRACTIONS IN THE MIXTURE THEREBY CONTACTING SAID EVAPORATING